1. Technical Field
This invention relates to the cutting of food product with hydraulic food cutting apparatus. In particular it relates to an improved blade assembly for cutting elongated segments of food product of small cross-sectional areas.
2. Background Art
There are three basic methods of preserving processed food, the first is canning, the second is freezing, and the third is dehydrating. Until now, processed potatoes such as french fries and hash browns have been preserved only by freezing. In order to produce dehydrated potato product such as an instant mashed potatoes base, the processor must mechanically cut the potato into finely chopped pieces or flakes, or in the alternative, must completely break down the cellular structure of the potato in order to form an extruded, processed, mash which can then be dried and chipped. All of this has, until today, been done by means of mechanical cutting apparati which are, by their very design, cumbersome, of low tonnage capacity, and expensive.
As an alternative to mechanical cutters for vegetable products, a class of devices known as hydroknives have been developed. Hydroknives suspend the food product in a carrier medium, usually water, and pump it through an alignment and acceleration tube which is similar in shape and function to the front half of a venturi into a longitudinal passageway holding a cutter blade assembly. The food product, traveling at speeds approximating 60 feet per second, impinges against the cutter blade assembly and is thereby sheared into a plurality of segments. Such hydroknife cutting apparati have the distinct advantage of higher capacity when compared to mechanical cutters, but until now, have been limited as to the smallness of the segmental size which can be cut. As a practical matter, the smallest size that is normally cut with a conventional hydroknife is approximately 0.08 square inches in cross-sectional area, which is the size of a standard french fry. Smaller cuts such as those for European style french fries, shoestring french fries, hash browns and the like, are made mechanically.
F. G. LAMB, ET AL., U.S. Pat. No. 3,109,468, discloses a typical hydraulic cutting apparatus wherein the food product to be cut, namely potatoes, are dropped into a tank filled with water and then pumped through conduit into an alignment chute wherein the potatoes are aligned and accelerated to a high speed before impinging upon a cutter blade assembly where the potato core is cut into a plurality of french fries and the peripheral area of potato is sliced off and diverted from the main flow of core product for later retrieval for other uses. LAMB further teaches a cutter blade assembly for producing potato segments having a large square cross-sectional area. The outermost blades extend the full length of the cutting assembly while the inner blades decrease in length as they are disposed closer and closer to the longitudinal axis of the cutting apparatus.
The problem with the cutter blade assembly as taught by LAMB, is that it produces potato segments which have a relatively large cross-sectional area and a high percentage of segments that are defective. A certain percentage of the potato segments will have feather cuts on their cornered edges and some will have substantial cell damage as a result of the compression experienced within the cutter blade assembly. Also, in practice it has been found that attempts to reduce segment size by simply adding more cutting knives to the apparatus as taught by LAMB, and thereby reducing the cross-sectional area of the cut product, results in frequent clogging of the cutter apparatus.
To date, the current state of the art has no solution for the clogging problem experienced when attempting to cut segments of small cross-sectional area, and only a partial and inadequate solution to the feathered cut problem. The percentage of segments having feathered cuts can be reduced, but not eliminated, by preheating the uncut food product to between 90.degree. F. to 120.degree. F. While this does not eliminate feathered cuts, it is the best that the prior art had to offer.
BROWN, ET AL., U.S. Pat. No. 4,300,429, teaches a cutter blade assembly which cuts french fry strips of varying cross-sectional area so as to compensate for the non-uniform solids content between the center of the potato and the peripheral areas so that the end product french fries will cook at a uniform rate. The cutter blade assembly as taught by BROWN provides an end product having a cross-sectional area which is smaller than that as taught by LAMB, but not as small as that necessary for shoestring potatoes or dehydrated food products.
In its preferred embodiment, the BROWN device has blade spacings which produce a plurality of french fries having cross-sectional areas of approximately 0.08 square inches. Small potato strings on the other hand, especially those suitable for dehydration, typically have cross-sectional areas of approximately 0.0062 square inches, corresponding to almost a 1300% reduction in cross-sectional area. Increasing the number of blades of BROWN, and therefore decreasing the spacing between blades so as to decrease the resulting cross-sectional area of the food segment, will result in clogging of the cutter blade assembly.
Additionally, the cutter assembly as taught by BROWN, produces a cut french fry which has feathered edges and substantial damage to the cells of the potato. This damage is a result of turbulent flow and the food segments being compressed within the individual passages created by the cutting blades.
As a general rule it can be said that adding more cutting blades to these devices in order to decrease the cross-sectional area of the segments of cut food product will result in frequent clogging of the cutter blade assembly and a substantial decrease in the quality of the final product resulting from feathered edges and broken segments caused by the multiple and repeated impingements of the cut food product against the various blades in the cutter assembly. It is not known how or what causes feathered cuts other than it is known that there is an extremely turbulent flow of carrier medium through the cutter blade assembly and that the cut food segments, either in the process of being sheared from the food product core, or at some later time impinge either upon a multiple number of blades, or the same blade in a repeated oscillating fashion.
Additionally, the typical cutter assembly has an array of blades which cut the four sides of each segment simultaneously, thus causing compressive forces in the cut food segments. This results in cell damage which degrades the quality of the product. Additional problems resulting from these compressive forces are increase turbulent flows and possible pressure differentials across the passageway which alters and degrades laminar flow of the product through the cutter blade assembly.
If a hydraulic cutter blade assembly such as that taught by the present invention were developed which is capable of producing high quality cut food segments having a cross-sectional area as small as 0.0062 square inches, then a vast number of food products could be produced with the use of a high capacity hydroknife cutting system as opposed to mechanical cutter blades. Some of these products, and perhaps the most important would be the ability to cut strings or shoestring segments of potato having a cross-sectional area of 0.0062 square inches which is particularly well suited to blanching and drying processes to produce a basic dehydrated potato food product which can be processed into a variety of different final products depending upon regional culinary tastes and preferences. Another benefit would be the ability to mass produce high quality shoestring or European style french fries.
What is needed is a hydraulic cutter blade assembly which is capable of producing potato string cuts when used in a typical hydraulic cutting apparatus, resulting in the production of potato strings that are the full length of the potato. And further, a hydraulic cutting blade assembly capable of producing potato strings at substantially larger production volumes than possible with present mechanical cutting apparatus. Also what is needed is a cutting blade assembly which reduces feather cuts and virtually eliminates cell damages caused by unnecessary compression of the cut food segments.
Accordingly, it is an object of this invention to provide a cutter blade assembly which can be utilized in a hydraulic food cutting apparatus to cut a food product into elongated segments, each having a substantially smaller cross-sectional area than was previously possible using hydraulic food cutters, and further capable of producing elongated string cuts of large, medium or small cross-sectional areas, which are free from feather cuts and cell compression damage.